JP5262156B2 - Solid polymer fuel cell and manufacturing method thereof - Google Patents

Description

  The present invention relates to a polymer electrolyte fuel cell and a method for producing the same. More specifically, the surface treatment is performed on the electrode catalyst layer to change the surface from water-repellent to hydrophilic, and the surface treatment is performed. The present invention relates to a solid polymer fuel cell having an improved output in a low load region, particularly under low humidification conditions, and a method for manufacturing the same.

  In recent years, fuel cells that have high energy conversion efficiency and do not generate harmful substances due to power generation reactions have attracted attention. As one of such fuel cells, a polymer electrolyte fuel cell that operates at a low temperature of 100 ° C. or lower is known.

  A polymer electrolyte fuel cell has a basic structure in which a solid polymer membrane as an electrolyte is disposed between a fuel electrode and an air electrode. A fuel gas containing hydrogen is contained in the fuel electrode, and a gas containing oxygen is contained in the air electrode. It is a device that supplies and generates power by the following electrochemical reaction.

Fuel electrode: H ₂ → 2H + 2e ⁻ (1)
Air electrode: 1 / 2O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O (2)
The fuel electrode and the air electrode have a structure in which an electrode catalyst layer and a gas diffusion layer are laminated. The respective electrode catalyst layers are arranged opposite to each other with the solid polymer membrane interposed therebetween to constitute a fuel cell. The electrode catalyst layer is a layer in which carbon particles supporting a catalyst are bound by an ion exchange resin (electrolyte). The gas diffusion layer becomes a passage for the oxidant gas and the fuel gas.

  In the fuel electrode, hydrogen contained in the supplied fuel becomes hydrogen ions and electrons as shown in the above formula (1). Among these, hydrogen ions move inside the solid polymer electrolyte membrane toward the air electrode, and electrons move to the air electrode through an external circuit. On the other hand, in the air electrode, oxygen contained in the oxidant gas supplied to the air electrode reacts with hydrogen ions and electrons that have moved from the fuel electrode, and water is generated as shown in the above formula (2). In this way, in the external circuit, electrons move from the fuel electrode toward the air electrode, so that electric power is taken out.

However, there is a problem that the voltage decreases as the device is operated for a long time. That is, in the operation of fuel cells for automobiles, households, cogeneration, etc., the potential of the air electrode under normal power generation is 0.6 V or more. Further, when the fuel cell is started and stopped, a small amount of air is mixed into the fuel electrode side, and as a result, the potential of the air electrode becomes 1.2 V or more. In the state where the potential of the air electrode is 0.6 V or more, the oxidation reaction shown in the following formula occurs, and the carrier carbon is oxidatively corroded.
C + H ₂ O → CO + 2H ⁺ + 2e ⁻ : 0.52V
C + 2H ₂ O → CO ₂ + 4H ⁺ + 4e ⁻ : 0.21V

  On the other hand, in the fuel electrode, when the supply of hydrogen is insufficient, a predetermined current density is maintained, so that an electrolysis reaction of water or oxidation of the carbon support may occur instead of the oxidation reaction of hydrogen. is there.

  For this reason, a carbon carrier (hereinafter, highly crystallized carbon) in which the crystallinity of carbon is increased by treatment at a high temperature of 2000 ° C. or higher and the oxidation resistance is improved has been proposed.

  However, highly crystallized carbon is more water repellent. Therefore, when protons move from the fuel electrode to the air electrode, the water in the electrolyte membrane on the fuel electrode side also moves simultaneously with the protons, so the water in the electrolyte membrane on the fuel electrode side decreases, preventing proton conduction (So-called dry-up) becomes prominent. In addition, there is a problem that the power generation characteristics are particularly deteriorated in a low load region, particularly under low humidification conditions with little water generated by power generation.

  Therefore, a technique for preventing dry-up and improving battery characteristics in a low load region under low humidification conditions is highly desired.

As an effective solution for this dry-up, it is known to impart hydrophilicity to the catalyst layer (Patent Document 1). For example, an oxygen plasma treatment is directly applied to amorphous carbon particles. However, when oxygen plasma treatment is directly applied to particles, it is difficult to uniformly perform plasma treatment, and hydrophilic groups are not sufficiently formed (Patent Document 2). ). In addition, there is an example in which the transfer catalyst layer containing amorphous carbon is subjected to atmospheric pressure plasma treatment, but it is difficult to efficiently treat the inside of the catalyst layer because the mean free process is low (Patent Document 3). As a result, there is a problem that particularly highly crystallized carbon particles that have been sufficiently hydrophilic-treated efficiently cannot be obtained.
JP 2004-185900 A JP-A-57-159856 JP 2007-242447 A

  The purpose of the present invention is to prevent dry-up by hydrophilizing the electrocatalyst layer containing highly crystallized carbon in a simple manner, and output in a low load region, particularly under low humidification conditions with little generated water. It is an object to provide an improved polymer electrolyte fuel cell and a method for manufacturing the same.

In order to solve the above problems, the present inventors have made extensive studies and as a result, obtained the following knowledge.
That is, by performing oxygen plasma treatment under high vacuum on the surface of the electrode catalyst layer using a reactive ion etching apparatus, the mean free process is increased, and the inside of the pores of the catalyst layer can be effectively subjected to oxygen plasma treatment. . As a result, the water repellency of the highly crystallized carbon particles was improved, and it was found that the output in a low load region was improved particularly under low humidification conditions with little water generated by power generation.

The invention according to claim 1 is a polymer electrolyte fuel cell comprising a membrane electrode assembly in which electrode catalyst layers containing highly crystallized carbon are bonded to both surfaces of a solid polymer electrolyte membrane, The solid polymer fuel cell is characterized in that at least one surface of the electrode catalyst layer in contact with the molecular electrolyte membrane is provided with a hydrophilic group by high vacuum oxygen plasma etching treatment .
The invention according to claim 2 is characterized in that the highly crystallized carbon has at least one selected from graphitic carbon, carbon nanotube, nanohorn and fullerene. Type fuel cell.
Invention of Claim 3 is a manufacturing method of a polymer electrolyte fuel cell provided with the membrane electrode assembly by which the electrode catalyst layer containing highly crystallized carbon was joined to both surfaces of the solid polymer electrolyte membrane, A method for producing a solid polymer fuel cell, wherein a surface of at least one of the electrode catalyst layers in contact with the solid polymer electrolyte membrane is subjected to a high vacuum oxygen plasma etching treatment to impart a hydrophilic group.

A solid polymer fuel cell according to claim 1 of the present invention is a solid polymer comprising a membrane electrode assembly (MEA) in which electrode catalyst layers containing highly crystallized carbon are bonded to both surfaces of a solid polymer electrolyte membrane. In the fuel cell, at least one surface of the electrode catalyst layer in contact with the solid polymer electrolyte membrane is provided with a hydrophilic group by a high vacuum oxygen plasma etching treatment , has a high mean free path, From the inside of the electrode catalyst layer to the inside of the electrode catalyst layer, the water repellency of the electrode catalyst layer is improved, the dry-up is improved, and the output in a low load region is improved particularly under low humidification conditions.

  In the polymer electrolyte fuel cell according to claim 2 of the present invention, the highly crystallized carbon has at least one selected from graphitic carbon, carbon nanotube, nanohorn, and fullerene, and the oxidation resistance is improved. There is a remarkable effect.

According to a third aspect of the present invention, there is provided a method for producing a polymer electrolyte fuel cell, wherein at least one surface of the electrode catalyst layer in contact with the polymer electrolyte membrane is subjected to high-vacuum oxygen plasma etching treatment to impart a hydrophilic group Therefore, the mean free path is high, more hydrophilic groups can be introduced from the pores to the inside of the electrode catalyst layer, the water repellency of the electrode catalyst layer is improved, the dry-up is improved, and the load is low especially under low humidification conditions. There is a remarkable effect that a polymer electrolyte fuel cell with improved output in the region can be obtained.

  Since the electrode catalyst layer containing highly crystallized carbon becomes water repellent by crystallization, the power generation characteristics are deteriorated particularly in a low load region under low humidification conditions. Therefore, by surface-treating the electrode catalyst layer, the water repellency of the highly crystallized carbon contained in the electrode catalyst layer is improved, and the effect of improving the power generation characteristics in the low load region under low humidification conditions can be obtained. .

  A polymer electrolyte fuel cell has a structure in which a pair of electrode catalyst layers are arranged on both sides of a polymer electrolyte membrane called a membrane electrode assembly (MEA), and hydrogen is formed on one of the electrode catalyst layers. And a structure sandwiched between a pair of separator plates formed with a gas flow path for supplying an oxidant gas containing oxygen to the other electrode catalyst layer. Here, the electrode supplying the fuel gas is the fuel electrode, and the electrode supplying the oxidant is the air electrode.

  FIG. 1 shows a schematic cross-sectional view of a membrane electrode assembly in the present invention. The membrane electrode assembly (MEA) 12 of the present invention has a structure in which an electrode catalyst layer 2 and an electrode catalyst layer 3 are bonded to both surfaces of a solid polymer electrolyte membrane 1. FIG. 2 shows an exploded sectional view of an example of the polymer electrolyte fuel cell of the present invention. In the polymer electrolyte fuel cell of the present invention, the air electrode side gas diffusion layer 4 and the fuel electrode side gas diffusion layer 5 are arranged so as to face the electrode catalyst layer 2 and the electrode catalyst layer 3 of the membrane electrode assembly 12. Is done. Thereby, the air electrode 6 and the fuel electrode 7 are comprised, respectively. A set of separators 10 made of a conductive and impermeable material is provided, which includes a gas flow path 8 for gas flow and a cooling water flow path 9 for cooling water flow on the opposing main surface. For example, hydrogen gas is supplied as a fuel gas from the gas flow path 8 of the separator 10 on the fuel electrode 7 side. On the other hand, a gas containing oxygen, for example, is supplied as an oxidant gas from the gas flow path 8 of the separator 10 on the air electrode 6 side.

  The solid polymer fuel cell shown in FIG. 2 has a so-called single cell structure with a solid polymer electrolyte membrane 1, electrode catalyst layers 2, 3, and gas diffusion layers 4, 5 sandwiched between a pair of separators. Although it is a molecular type fuel cell, in the present invention, a plurality of cells can be stacked via the separator 10 to form a fuel cell.

(Solid polymer electrolyte membrane)
The solid polymer electrolyte membrane used in the present invention is a proton-conductive membrane, and in particular, a perfluoro type sulfonic acid membrane, for example, Nafion (registered trademark of DuPont), Flemion (Asahi Glass Co., Ltd.) as product names. And Aciplex (registered trademark of Asahi Kasei Co., Ltd.). Further, a hydrocarbon film such as sulfonated PEEK (polyether ether ketone), PES (polyether sulfone), or PI (polyimide) can also be used.

  The polymer electrolyte in the electrode catalyst layer used in the present invention is preferably the same material as the solid polymer electrolyte membrane.

(Production of electrode catalyst layer)
The electrode catalyst layer can be produced on the solid polymer electrolyte membrane from the following four steps.
Step (1): A catalyst ink is prepared by dispersing highly crystallized carbon particles carrying a catalyst substance and a polymer electrolyte in a dispersion solvent.
Step (2): The catalyst ink is applied on a substrate that is a transfer sheet or a gas diffusion layer to form an electrode catalyst layer.
Step (3): Next, it is dried.
Step (4): Surface treatment is performed on the electrode catalyst layer transfer sheet or the gas diffusion layer on which the electrode catalyst layer is formed.
Step (5): The surface-treated electrode catalyst layer and the solid polymer electrolyte membrane are joined.

(Process 1)
The solvent used as a dispersion medium for the catalyst ink is not particularly limited as long as it can be dissolved or dispersed as a fine gel in a highly fluid state of the polymer electrolyte without eroding the catalyst particles and the polymer electrolyte.
However, it is desirable to include at least a volatile liquid organic solvent, and is not particularly limited, but is not limited to methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol. Alcohols such as alcohol, isobutyl alcohol, tert-butyl alcohol, pentanole, ketone solvents such as acetone, methyl ethyl ketone, pentanone, methyl isobutyl ketone, heptanone, cyclohexanone, methylcyclohexanone, acetonyl acetone, diisobutyl ketone, tetrahydrofuran , Dioxane, diethylene glycol dimethyl ether, anisole, methoxytoluene, dibutyl ether and other ether solvents, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, ethylene glycol Le, diethylene glycol, diacetone alcohol, 1-methoxy-2-propanol polar solvents is used. Moreover, what mixed 2 or more types of these solvents can also be used.

  In addition, those using lower alcohol as the solvent have a high risk of ignition, and when using such a solvent, it is preferable to use a mixed solvent with water. Water that is compatible with the polymer electrolyte may be contained. The amount of water added is not particularly limited as long as the polymer electrolyte is not separated to cause white turbidity or gelation.

  The catalyst substance used in the present invention (hereinafter sometimes referred to as catalyst particles or catalyst) includes platinum, palladium, ruthenium, iridium, rhodium, osmium, platinum group elements, iron, lead, copper, chromium, cobalt, A metal such as nickel, manganese, vanadium, molybdenum, gallium, aluminum, or an alloy thereof, an oxide, a double oxide, or the like can be used. Moreover, since the activity of a catalyst will fall when the particle size of these catalysts is too large, and stability of a catalyst will fall when too small, 0.5-20 nm is preferable. More preferably, 1-5 nm is good.

(Highly crystallized carbon)
Highly crystallized carbon carrying these catalysts has better oxidation resistance than amorphous carbon. As the highly crystallized carbon, not only graphitic carbon but also new carbon materials such as carbon nanotubes, nanohorns and fullerenes can be used. The G / D ratio of highly crystallized carbon is more preferably 10 or more. Here, G is the maximum peak intensity within a range of 1560 to 1600 cm ⁻¹ (a band derived from high crystallinity) in a spectrum obtained by a resonance Raman scattering measurement method. Moreover, D is the maximum peak in the range of 1310 to 1350 cm ⁻¹ (crystal defect and band derived from amorphous carbon) in the spectrum obtained by the resonance Raman scattering measurement method. By setting the G / D ratio of the highly crystallized carbon to 10 or more, the crystallinity increases and the oxidation resistance is improved. This is the highly crystallized carbon in the present invention.
On the other hand, if the particle size of the highly crystallized carbon particles is too small, it is difficult to form an electron conduction path. If the particle size is too large, the gas diffusibility of the catalyst layer is lowered or the utilization factor of the catalyst is lowered. ˜1000 nm is preferred. More preferably, 10-1000 nm is good.

  The pore volume of the electrode catalyst layer depends on the composition of the catalyst ink and the dispersion conditions, and varies depending on the amount of the polymer electrolyte, the type of the dispersion solvent, the dispersion method, the dispersion time, etc., so at least one of these, preferably It is preferable to use two or more in combination to form the electrode catalyst layer so that the pore volume of the electrode catalyst layer increases from the side close to the gas diffusion layer toward the solid polymer electrolyte membrane.

  In order to disperse the carbon particles supporting the catalyst substance, a dispersant may be included. Examples of the dispersant include an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant.

  When the amount of the polymer electrolyte in the catalyst ink used in the present invention is increased, the pore volume is generally reduced. On the other hand, when the carbon particles are increased, the pore volume generally increases. Also, the use of a dispersant generally reduces the pore volume.

  The viscosity and particle size of the catalyst ink can be controlled by the conditions for the dispersion treatment of the catalyst ink. Distributed processing can be performed using various apparatuses. Examples thereof include a ball mill, a roll mill, a shear mill, a wet mill, and an ultrasonic dispersion treatment. Moreover, you may use the homogenizer etc. which stir with centrifugal force.

If the solid content in the catalyst ink is too high, the viscosity of the catalyst ink will be high and cracks will easily occur on the surface of the catalyst layer. Conversely, if it is too low, the film formation rate will be very slow and productivity will be reduced. Therefore, the content is preferably 1 to 50% by mass.
The solid content is composed of carbon particles supporting catalyst material (hereinafter referred to as catalyst-supported carbon) and a polymer electrolyte. Increasing the content of catalyst-supported carbon increases the viscosity even with the same solid content. Lower.
Therefore, the ratio of the catalyst-supporting carbon to the solid content is preferably 10 to 80% by mass. Further, the viscosity of the catalyst ink at this time is preferably about 0.1 to 500 cP, more preferably 5 to 100 cP. Further, the viscosity can be controlled by adding a dispersing agent when the catalyst ink is dispersed.

(Process 2)
As a method for forming the catalyst layer, a coating method such as a dipping method, a screen printing method, a roll coating method, or a spray method is generally used.

  A gas diffusion layer or a transfer sheet can be used for the substrate used in the present invention.

The gas diffusion layer is generally made of a material having gas diffusibility and conductivity. For example, carbon paper or carbon cloth can be used.
Before applying the catalyst ink, an eye layer may be formed on the gas diffusion layer in advance. The mesh layer is a layer that prevents the catalyst ink from penetrating into the gas diffusion layer, and deposits on the mesh layer to form a three-phase interface even when the coating amount is small. Such a filler layer can be formed, for example, by kneading carbon particles and a fluorine resin and burning them at a temperature equal to or higher than the melting point of the fluorine resin. As the fluororesin, polytetrafluoroethylene (PTFE) or the like can be used.

  Transfer sheets include, for example, polyimide, polyethylene terephthalate (PET), polyparvanic acid aramid, polyamide (nylon), polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, polyetherimide, polyacrylate, polyethylene naphthalate, etc. Can be mentioned.

  In addition, heat resistance of ethylene tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroperfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), etc. Fluorine resin can also be used.

  The thickness of the transfer substrate is usually about 6 μm to 100 μm, preferably about 10 μm to 50 μm, more preferably about 15 μm to 30 μm, from the viewpoints of handleability and economy.

(Process 3)
The transfer catalyst sheet can be produced by fixing a substrate on a plate, applying a catalyst ink on the substrate with a doctor blade, and drying in an oven set at 20 ° C to 150 ° C.

  Although it depends on the drying temperature, the drying time is usually about 1 to 30 minutes.

  The thickness of the electrode catalyst layer in the transfer catalyst sheet is preferably 1 to 50 μm, and more preferably 10 μm or less. The reason is that if the electrode catalyst layer is too thick, the surface treatment effect may not be applied in detail.

(Process 4)
Examples of the surface treatment method for the electrode catalyst layer include atmospheric pressure plasma treatment, corona discharge treatment, UV ozone treatment, electron beam treatment, oxygen plasma ashing treatment, and reactive ion etching treatment. A hydrophilic group can be imparted by these treatments.

  Among these, as the surface treatment of the electrode catalyst layer, oxygen plasma etching treatment under high vacuum is preferable. The oxygen plasma etching treatment is a method for powerfully treating the electrode catalyst layer by implanting ions extracted from plasma generated under a high vacuum into the electrode catalyst layer. By applying a voltage to oxygen ions generated under high vacuum, oxygen ions can be implanted into the electrode catalyst layer. By performing oxygen plasma etching under high vacuum, the mean free path is high, and hydrophilicity can be efficiently imparted to highly crystallized carbon in the details of the electrode catalyst layer in a short time.

  As a surface treatment of the electrode catalyst layer, the oxygen plasma etching treatment can be strongly hydrophilized compared to other surface treatment methods, and the treatment depth of the hydrophilization treatment can be increased. . When highly crystallized carbon is used as the catalyst-supporting carbon in the catalyst layer, a high oxygen plasma etching process can be suitably used.

  The atmosphere in the chamber is not limited except that oxygen is contained.

When performing the high vacuum oxygen plasma treatment, the degree of vacuum is preferably about 10 ⁻² to 10 ⁻¹ Torr, and the temperature is preferably about room temperature to about 100 ° C. The voltage frequency is preferably 1 to 50 MHz and the output is preferably 20 to 250 W.

(Process 5)
The surface-treated transfer catalyst sheet or the electrode catalyst layer on the gas diffusion layer is joined to the solid polymer electrolyte membrane. A membrane / electrode assembly is formed by placing electrode catalyst layers formed on a transfer sheet or gas diffusion layer on both sides of a solid polymer electrolyte membrane and performing hot pressing.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

(Example)
(Preparation of catalyst ink)
A platinum-supported highly crystallized carbon catalyst and a 20% by mass polymer electrolyte solution (Nafion: registered trademark, manufactured by Dupont) are mixed in a solvent, and dispersed with a planetary ball mill (trade name: Pulverisete 7, manufactured by FRITSCH). went. Ball mill pots and balls made of zirconia were used.
A catalyst ink was prepared in which the composition ratio of the starting material was 2: 1 by mass ratio of platinum-supported highly crystallized carbon and polymer electrolyte (Nafion: registered trademark, manufactured by Dupont).
The solvent was ethanol and methanol at a volume ratio of 1: 1. The solid content was 10% by mass.

(Base material)
A PTFE sheet was used as a transfer sheet.
(Production of electrode catalyst layer)
The substrate was fixed on a plate in which water at 25 ° C. was circulated, the catalyst ink was applied onto the substrate with a doctor blade, and the electrode catalyst layer was prepared by drying in an oven set at 70 ° C. for 30 minutes. . The thickness of the electrode catalyst layer was adjusted so that the amount of platinum supported was 0.3 mg / cm ² .

(Electrode catalyst layer surface treatment)
The transfer sheet on which the electrode catalyst layer was formed was subjected to surface treatment using a reactive ion etching apparatus (manufactured by ULVAC). The treatment conditions were an output of 100 W, an oxygen gas of 100 sccm, and a chamber pressure of 0.02 Torr for 60 seconds.

(Production of MEA)
The transfer sheet of Example 1 subjected to the surface treatment and the transfer sheet of Comparative Example 1 not subjected to the surface treatment were punched into 5 cm ² squares, and both sides of the polymer electrolyte membrane (Nafion: registered commercial review, manufactured by Dupont) were used. The transfer sheet was placed so as to face each other, and hot pressing was performed under the conditions of 130 ° C. and 6.0 × 10 ⁶ Pa to obtain an MEA as shown in FIG.

(Power generation characteristics)
The MEA was bonded so as to sandwich a carbon cloth as a gas diffusion layer, and installed in a power generation evaluation cell (manufactured by NF Circuit Design Block). Using this fuel cell measurement device (trade name: GFT-SG1, manufactured by Toyo Technica Co., Ltd.), current voltage measurement was performed under the following operating conditions at a cell temperature of 80 ° C. Hydrogen was used as the fuel gas and air was used as the oxidant gas, and the flow rate was controlled at a constant utilization rate. The back pressure was 100 kPa.
Low humidification: anode 20% RH, cathode 20% RH

The power generation characteristics of the MEAs produced in Comparative Example 1 and Example 1 were examined. As a result, it was confirmed that Example 1 was improved in the low load region (0.15 A / cm ² ).

  From the above results, it was confirmed that by applying a surface treatment to the electrode catalyst layer, dry up of highly crystallized carbon was improved, and power generation characteristics were improved in a low load region under low humidification conditions.

  By hydrophilizing the electrode catalyst layer containing highly crystallized carbon as in the present invention in a simple manner, dry-up is prevented, and it is particularly excellent in low-humidity conditions under low humidification conditions with little water generated by power generation. It has a remarkable effect of exhibiting power generation characteristics, and thus has high industrial utility value.

It is a cross-sectional schematic diagram of the membrane electrode assembly in this invention. It is an exploded sectional view of an example of a polymer electrolyte fuel cell of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solid polymer electrolyte membrane 2 Electrode catalyst layer 3 Electrode catalyst layer 4 Air electrode side gas diffusion layer 5 Fuel electrode side gas diffusion layer 6 Air electrode 7 Fuel electrode 8 Gas flow path 9 Cooling water flow path 10 Separator 12 Membrane electrode assembly ( MEA)

Claims (3)

A solid polymer fuel cell comprising a membrane electrode assembly in which electrode catalyst layers containing highly crystallized carbon are bonded to both surfaces of a solid polymer electrolyte membrane, at least one in contact with the solid polymer electrolyte membrane A solid polymer fuel cell, wherein the surface of the electrode catalyst layer is provided with a hydrophilic group by high vacuum oxygen plasma etching .   2. The polymer electrolyte fuel cell according to claim 1, wherein the highly crystallized carbon includes at least one selected from graphitic carbon, carbon nanotube, nanohorn, and fullerene. A method for producing a polymer electrolyte fuel cell comprising a membrane electrode assembly in which electrode catalyst layers containing highly crystallized carbon are bonded on both sides of a solid polymer electrolyte membrane, wherein the solid polymer electrolyte membrane is in contact with the solid polymer electrolyte membrane A method for producing a polymer electrolyte fuel cell, comprising subjecting at least one surface of the electrode catalyst layer to a high vacuum oxygen plasma etching treatment to impart a hydrophilic group.

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